Storm Forecast
Valid: Fri 11 Nov 2011 06:00 to Sat 12 Nov 2011 06:00 UTC
Issued: Thu 10 Nov 2011 20:57
Forecaster: TUSCHY

SYNOPSIS

Stable omgea pattern persists. Any thunderstorm activity remains confined to parts of the Mediterranean and NW-Europe. Otherwise stable conditions prevail.

DISCUSSION

... General thunderstorm areas ...

At 21 Z [10th Nov], a mature low is placed SW of Ireland. A pronounced warm conveyor belt aims towards UK and Ireland and affects that area during the daytime hours. Convective activity is sporadic beneath an ill defined dry slot .

We expect a gradual increase in DMC probabilities during the morning hours onwards, as cold air at 500 hPa overspreads the warm sector and a cold front moves in from the west/southwest. The main problem seems to be a marginal BL moisture quality , so main CAPE signals right now are confined to the offshore areas and SW-UK. LL shear is enhanced with better LL CAPE offshore and along the coasts, so wie don't want to rule out an isolated tornado event. Current confidence in a more robust severe risk is limited by very low-end CAPE, so we did not issue a level 1 for that event. Strong wind gusts and marginal hail accompany stronger thunderstorms. The activity slowly diminishes during the evening hours onwards.

Scattered thunderstorms are still forecast beneath a diffuse upper wave over the E-CNTRL Mediterranean. Especially next to Cyprus, DLS of 15-20 m/s may assist in a better organized multicell with large hail and strong wind gusts. Thunderstorms shift southwards as cold front moves in from Greece during the afternoon. Isolated coverage of storms limits the severe risk and hence no level was issued.

An isolated thunderstorm event is possible west of Portugal during the night/early morning hours. However those storms first become more interesting/widespread after 06 Z.